Indiana Administrative Code
Title 675 - FIRE PREVENTION AND BUILDING SAFETY COMMISSION
Article 30 - INDIANA BOILER AND PRESSURE VESSEL RULES
Rule 10 - Existing Installations of Heating Boilers
Section 10-12 - Safety valves for low pressure steam heating boilers; dimensions and capacity

(a) Each low pressure steam heating boiler shall have one (1) or more safety valves of the spring-pop type adjusted and sealed to discharge at a pressure not to exceed fifteen (15) psig.

(b) Each safety valve for a low pressure steam heating boiler that has a diameter three-fourths (3/4) inch or larger shall have a substantial device that will positively lift the disk from its seat at least one-sixteenth (1/16) inch when there is no pressure on the boiler. The seats and disks shall be of suitable material to resist corrosion.

(c) No safety valve for a low pressure steam heating boiler shall be smaller than three-fourths (3/4) inch and shall have a substantial device that will positively lift the disk from its seat at least one-sixteenth (1/16) inch when there is no pressure on the boiler. The seats and disks shall be of suitable material to resist corrosion.

(d) The minimum capacity of the valve or valves shall be governed by the capacity marking on the boiler called for in Section IV of the ASME B&PVC.

(e) The minimum valve capacity in pounds per hour shall be determined by dividing the maximum Btu output at the boiler nozzle obtained by the firing of any fuel for which the unit is designed by one thousand (1,000). In every case the requirements of subsection (f) shall be met.

(f) The steam safety valve capacity for each low pressure steam heating boiler shall be such that with the fuel-burning equipment installed, and fires at a maximum rate, the pressure of the low pressure steam heating boiler shall not exceed fifteen (15) psig with all safety valves open.

(g) When operating conditions are changed or additional boiler heating surface is installed, the valve capacity shall be checked and increased if necessary to meet the new conditions and be in accord with subsection (f). The additional valves required may be installed on the outlet pipe providing there is no intervening valve nor any other branching pipes between additional valves and the boiler.